The present invention relates to an apparatus for forming vertical stacks of documents, such as magazines or newspapers, from documents which are sequentially delivered to the apparatus, and for then conveying the stacks sequentially along a path of travel while maintaining the vertical alignment of the stacks.
Modern stack forming machines are able to rapidly form vertical stacks of documents from documents sequentially delivered thereto, and to eject the stacks horizontally onto a longitudinally extending driven conveyor by which the stacks are transported to further processing operations, such as binding and labeling stations. When such machines are run at high speed, the ejector must be cycled very rapidly, and the rapid ejection of the stacks tends to cause misalignment or shingling in the forward or longitudinal direction, as illustrated in FIG. 2 of the accompanying drawings. Also, the documents may slide laterally.
In an attempt to alleviate the shingling and alignment problems, it has been proposed to mount lugs or paddles on the conveyor which engage the leading end of each stack causing it to square up, and the lugs or paddles are then moved out of the way to permit the stack to continue its advance. This arrangement has not been totally satisfactory however since the movement of the lugs or paddles requires significant equipment and time, and thus production speeds are limited.
It is accordingly an object of the present invention to provide an apparatus for forming stacks of documents and ejecting the formed stacks onto a longitudinally extending conveyor at high production speeds, and which is able to correct and/or maintain the vertical alignment of the stacks as they are conveyed along the conveyor.
It is also an object of the present invention to provide an apparatus of the described type which squares the stacks in both the longitudinal and lateral directions.